Liquid fuel atomizer or carburetor



j? 3L 1951 E. P. SHARP LIQUID FUEL ATOMIZER 0R CARBURETOR Filed Oct. 15,-1947 Patented July 31, 1951 LIQUID FUEL ATOMIZER'OR'CAREURETOR v Ernest P. Sharp, Forest Row, England, assigner of one-half Ato Stanley Charles Morrell, London,

England K I Application'October 15, 1947, Serial No. '780,007y l In Great Britain July 1, 1946 3 Claims.

This invention relates to carburetters or liquid fuelfatomisers for supplying combustible fuel and air mixtures to internal combustion engines, turbines and jet propulsion units hereafter referred to as internal combustion engines, and has more especial reference to those for use with piston type engines in which the reduction in pressure in the inlet manifoldduring the Working of the engine is utilised to raise liquid fuel from a storage receptacle or-tank to the atomiser or carburetter without recourse to a mechanical pump and without the oat chamber provided in conventional carburetters.

It is the object of the invention to provide such a carburetter which issimple and cheap to manufacture while being reliable, economical and ef- .y

icient in use. i

In a `carburetter orrliquid fuel atomiser according Ato the. invention comprising a fuel jet having an orifice regulated by a small tapered or conical valve hereinafter referred to as a needle jet to vary the fuel metering at the jet orice,the

mixture being formed with air induced as an annular stream around the jet and thence flowing inline therewith through a mixing chamber to the passage controlled by the throttle.

Preferably the jet needle and Ithe main throttle are arranged for rotation together, axial movement of the needle within the jet being effected by screw means and the needle being guided during such movement by bearing surfaces provided in the fuel duct leading to the jet.

The throttle may be of the ported disc or of the butterfly type, but preferably it is of barrel or hollow plug construction having a peripheral port or ports to control the passage of mixture from its open end, which forms a continuation of the mixing chamber, to the inlet manifold.

v The main air supply may be induced through a part spherical or toroidal annular intake duct past the jet, where it eiects entrainment of the liquid fuel. and thence through a Venturi-like rotation on a common shaft passing through the mixing chamber, longitudinal movement of the assembly being caused, upon rotation, by screw means to vary the fuel metering orice, or the throttle may be coupled by an external bridge to 2 the. needle stem which in' this case projects from the opposite end ofthe carburetter. i The carburetter according to the invention may operate in conjunction with a conventional fuel pump and iioat chamber, but preferably the care buretter itself utilises the suction in the inlet manifold yto raise fuel from the tank or reservoir, and advantageously in such case a main air inlet valveis provided in addition to or in place of a conventional independent choke and is coupled to the throttle and needle for simultaneous operation by a single control pedal or lever.

Reference will now. be had to the drawings in which two embodiments of the invention applied to fuel-lift carburetters not requiring a pump or float chamber are illustrated by way of example, andinwhich y I Figs. l and 2 are a central longitudinal sec-r tion and an end view respectively of a carburetter according to one embodiment,

Fig. 3 shows a modification of a detail thereof to a larger scale, and l Fig. 4 is a fragmentary View of a section si1ni` lar to Fig. l of the otherV embodiment.

Referring now tothe drawings and more particularly to Figs.rl and 2, a` hollow body member` I carries screwed into its front end a membery 2 formed ,with main air inlet ports 3 and a quasi hemispherical air inlet duct 4 converging on a jet 1, 8 and terminating ina Venturi-like constriction before merging into a wider cylindrical mixture passage in the body I. A port formed under thek body I, at rightangles to its axis, is controlled by a ported barrel throttle 5 having a cooperating port I0 whichregulates .passage of the mixture to the engine through a conduit 6 which is either connected to or forms part of the induction manifold.

The variable jet is located at the ycentre ofthe air intake duct 4 and on the axis of Ithe apparatus where it permits entrainment by the induced an nular air stream, of vliquid. fuel from a metering orifice 1 the effective area of which is varied in consonance with the movements of the throttle 5 by axial displacement of a needle valve 8 formed on a shaft 9 secured coaxially to the rear end of the throttle 5.

In the fuel lift carburetter illustrated, the liquid fuel is drawn directly from the fuel tank through a pipe (not shown) toa union I'2 containing a filter I3 and formed radially on a lcollar I4 clamped on a fuel conduit I5 screwed into the front of the air intake 2, such conduit having ports lliv which lead the fuel to the jet from an annular space I8 formed inside the collar I4.

A small quantity of primary air may be adthe nozzle 22 clear of the channels 23, the outer surface of the cap blending smoothly intothat of the air intake duct 4.

A flange 21 formed at the rear of the throttle 5 has a left hand thread and rides 'in a tapped portion of the body I so that rotation of "the throttle by means of an operating arm 28v linked in any appropriate manner to the accelerator pedal or Vlever will control the .admission of mixture to the linlet conduit 6 via the vthrottle port l0 while also causing a small axial movement of the throttle and needle assembly whereby the metering orifice is simultaneously varied Vby' the needle 8. The'rear end of the shaft 9 is threaded and screwed into the throttle 5 so that it can be adjusted axially to set the metering orifice datum and then be locked in the set position by a locking'nut 28. The arm 28 is formed with a clamp 4 It will be understood that the invention it not limited to the embodiments illustrated and, for instance, a gauze or similar mixing device may be fitted across the mixing chamber, while clutching means maybe provided to permit the main .air inlet valve .to'be operated independently when desired or a supplementary independent choke may be fitted.

Similarly, the throttle arrangement shown in Fig. .l'may be duplicated, the throttle having two diametrically opposite ports I0 to control the passageofmixturegto a pair of horizontal intake ducts each serving half the cylinders of a piston type engine.

While '.fuel .consumption has been found to be exceptionally low, still further economy may be p achieved yby the provision of an automatic or manually controlled extra air admission valve in the inlet duct 6.

f 'The 'throttle may be a ported disc valve similar to the main air inlet valve illustrated, `in which case the duct leading to the inlet manifold `may be a 4straight continuation of the mixing chamber. Alternatively the throttle may be of the butterfly type with its axis lying in the plane of the -at side of a D-section extension of the mixing chamber so as to Vcontrol the passage of mixture from such D-shaped duct to the mouth of 38 `adjustably mounted on the end of the rod r'9 and 'held by means of a clamping screw 3|. The arm carries at one end a ball 32 for universal comiecton to the accelerator pedal linkage,

while inthe fuel lift carburetter illustrated, its t other end is rigidly coupled by a bridge 34 to a tongue 31 formed on a ported disc 38 regulating themain air intake and rotatably held against the alii-,inlet ports 3 by means of a anged ring 3S secured to the intake member 2 by screws 40 and Acut away over an arc to pass the tongue 31. `-Since the main air intake valve 38 is thus coupled for ,rotation with the throttle, control of the "intake of air will be effected simultaneously with that cf the fuel and mixture 'by the varying register between the ports 3 and those of the main air valve 38, and the arrangement is more clearlyillustrated in Fig. '2, where a portion of thebodyis broken awa'y to show one of the ports falmost closed by the valve 38 when the rotating valve assembly is in the slow running position 'as determined by a screw-adjusted limit stop H against which the arm 28 comes to bear.

*An annular cap 42 screwed on to the rear end ofthe body l is locked by a screw 43 and serves to 'limit the axial travel of the throttle 5 while also mounting the stop 4l.

The primary air valve and port I8, 20 may be replaced by the arrangement shown in Fig. 3 and comprising a ball 50 urged by a spring 5I against a square seat 52 formed in a -hollow nut or cap 53.

Fig. 4 shows an alternative arrangement wherein the arm 28 is coupled by a bridge 63 to a lever 80 whereby to control a fuel needle valve 68 from the front of the carburetter by rotation of its stem B9. 'The internal shaft 9 is thus dispensed with and, since the valve stem 68 is itself threaded andfrides in the conduit I5 where it is tapped at 51, as the throttle 5 is opened the latter need not partake of the axial movement of the needle valve.

In this embodiment the metering orifice is formed in -a cap nozzle 64 having internal centralising ribs 65 with bearing surfaces to guide the valve -stem 65, and the supply of primary air is dispensed with, the projecting end of the stem 69 extending through a packing gland 66.

a `cylindrical or it 'may be polygonal inlet duct mounted at right angles thereto.

The main air intake duct may be arranged to pass air directly to the jet as an annular stream from the front of the carburetter, while the main air valve, `where provided, may be coupled directlyby a spider to the needle stem for rotation therewith. 4

As aforementioned, the -needle Vitself need not necessarily rotate with vthe throttle. Thus for example it may have a polygonal or splined shank riding in a fixed `guide while its stem is threaded and engaged by a tapped 'throttle for reciprocation upon rotation of the throttle.

Moreover, instead of the needle being associated for movement with the throttle, the jet nozale may be arranged to lrecipr-ocate over a stationary needle to provide variation of the metering orice 'in consonance with the throttle Amovement.

By fthe present invention an improved and simplified carburetter or liquid fuel atomiser for internal combustion engines is provided which is reliable and eicient in use, giving a low fuel consumption, while being easy and cheap to manufacture.

What I claim is:

1. A carburetter Vfor an internal combustion en- 4gine comprising in combination a body providing fa Venturi mixing chamber and a cylindrical housing'for a throttle 'in line with said mixing chamber, a fuel jet having an orifice at the mouth of the mixing chamber and co-axial therewith, a tapering fuel regulating valve reciprocable in said oriii'ce, an annular toroidal main air intake duct converging on said jet and leading from an annular series of air inlet ports to the Venturi mixing chamber, a ported annular air inlet valve for controlling said ports, a ported hollow plug throttle located in said housing between said chamber and the engine, a driving shaft coaxial in said throttle extending through the mixing chamber and mounting said fuel valve, means coupling said air inlet valve for rotation with said driving shaft and means operative, on turning of said shaft to eect opening of the throttle and air inlet valve, simultaneously to effect axial movement of the fuel valve in the jet orice to vary the supply of liquid fuel in consonance with the throttle and inlet valve opening.

2. A carburetter according to claim 1 wherein the jet is constructed as a double nozzle with an intermediate fuel space, the outer or cap nozzle being formed with the metering orifice while the inner nozzle has a fuel conduit coaxial with the jet the end of which conduit guides a cylindrical extension of the needle in its axial movement, and the fuel by-passing such guided portion of the needle through narrow channels connecting a portion of the conduit beyond its stroke with the intermediate fuel space.

3. A carburetter for an internal combustion engine comprising in combination a body providing a Venturi mixing chamber and having a tapped portion near one of its ends, a fuel jet having an orifice opposite said tapped portion of the body and coaxial therewith, a tapering fuel regulating valve reciprocable in said orifice, an annular toroidal main air intake duct converging on said jet and leading from an annular series of air inlet ports to the Venturi mixing chamber, a ported annular air inlet valve for controlling said ports, an externally screw-threaded ported hollow plug throttle located in the body between said chamber and the engine with its screw threads riding in said tapped portion of the body, a driving shaft coaxial in said throttle extending through the mixing chamber and mounting said fuel valve, means coupling said air inlet valve for rotation with said driving shaft and means operative, on turning of said shaft to effect opening of the throttle and air inlet valve, simultaneously to effect, through said screw threads on the throttle, axial movement of the fuel valve in the `iet orifice to vary the supply of liquid fuel in consonance with the throttle and inlet valve opening.

ERNEST P. SHARP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 810,792 McIntosh Jan. 23, 1906 938,894 Rapp Nov. 2, 1909 1,029,606 Guthrie June 18, 1-912 1,187,945 Van Briggle June 20, 1916 1,208,196 Pembroke Dec. 12, 1916 1,286,282 Gibson Dec. 3, 1918 1,327,233 Grant Jan. 6, 1920 1,516,276 Hauskins Nov. 18, 1924 1,550,434 Fluharty Aug. 18, 1925 1,691,487 Leveque Nov. 13, 1928 2,253,901 Ferguson Aug. 26, 1941 

